Today, I took a look at Google Labs’ Page Speed Online app to check the score of one of my sites. I was shocked to find out it was scoring really low at 59/100. Pathetic in my opinion since I consider site speed a huge priority (and so does Google in fact). I had just done a site update earlier in the week, so I was thinking that I had broken something. I checked the Page Speed Plugin for Firefox (part of Firebug), and just like I remembered, we were scoring really high at 94/100. I decided to take a look at the Page Speed for Chrome to see where that plugin would score us. It wasn’t as high as Firefox, but not nearly as low as the Online version; scoring at 81/100.
So my question to Google is this: Why the difference? Aren’t they running the same rules? Which score means more to Google? Between the browsers I would assume the rules being run in Firebug instead of straight through Chrome could cause a slight difference. Also perhaps the rendering engines for the browsers could account for some difference too. If anyone knows the answer for sure and which score I should really believe, I’d love to know!